All opinions are my own and do not necessarily reflect those of Novo Nordisk
A recent publication about efforts to find early indicators for autism recently came out in the journal Brain and reports an intriguing observation about brain size. The researchers sought to identify whether Magnetic Resonance Imaging (MRI) of the brains of infants and very young children could help to predict which children would go on to develop autism. Like many pilot studies of this sort, the experiment was done simply by looking. The researchers identified a cohort of newborn siblings of autistic children and also a control cohort without that risk factor and began taking MRI images of their brains at the age of between 6-9 months, and again at 12-15 months and 18-24 months. Prior research has shown that having a sibling with autism greatly increases the probability that a child will also develop autism, so in this situation the expectation was that some of the sibling group would develop autism and researchers would retrospectively be able to look at the data collected during the study and identify MRI features that correlated with development of disease, should any exist.
The impetus behind this is that previous research has not shown any definitive behavioral clues in infants (6 months or younger) that predict the development of autism. However, the earlier a child is diagnosed, the earlier behavioral interventions can be applied to help that child and his or her family cope with future challenges.
When researchers began looking at MRI images of the brains of these study participants, they identified an unexpected finding: in some of the children, they noticed a greater amount of cerebral-spinal fluid (CSF) surrounding their brains than in others. Through the application of image processing and quantifying tools, they were able to create a score for how much CSF a child had, and also to compare that score within and between children over time. Once all the study participants had reached 24 months or older, and behavioral assessments had been performed to provide an initial diagnosis of autism, the results were very clear that there was strong correlation between level of CSF during early development and a later diagnosis of autism. The researchers also found an independent association between brain volume itself and autism.
In discussing these findings, the researchers are admirably restrained, and point out the need for independent verification in much larger cohorts, both to prove this is not a one-time fluke, and also to provide measures of how sensitive and specific MRI measurements will be for predicting the development of autism. As they point out, in some children there was an accumulation of CSF without a later diagnosis of autism.
I wrote a few weeks back about another possible form of testing for autism, in that case centered around the presence of maternal autoantibodies to specific brain proteins. This new research is in that same vein of trying to find both a way to diagnose autism as early as possible, and also to get us closer to understanding autism’s causes. Finding the causes (and I believe there will be more than one) may get us closer to designing a cure.
To me there are several pretty exciting elements to this. For one, the researchers showed a correlation between amount of CSF and severity of autism symptoms, which is intriguing as it hints strongly that CSF levels are closely related to aspects of causation. The second exciting element is that while this technique does require structural MRI, the researchers point out that a general association of accelerated head size growth and autism has been seen before, and with additional confirmation and testing, a much simpler screening method based on measurements of head size might be a viable way to allow for testing for autism at a much earlier age. I’m all for non-invasive, low-tech solutions whenever appropriate and possible.
And third, this is exciting because, if confirmed, these metrics will provide a clear link between early, measurable biomarkers and the development of autism, and let me clarify what I mean by early: 6 months of age. The differences could possibly be seen earlier; we don’t know because the authors didn’t look. Why is 6 months important? Because it predates when the MMR vaccine is typically first given to children, and so this study is yet another piece of evidence that the MMR vaccine is not one of the causes of autism. Sadly, like most of the rest of the scientific evidence, this paper will be ignored by many of those who choose to still believe there is a link. But it’s important to keep working at understanding autism and where and when and how it starts, and this paper is another useful addition to the body of data.